It is the first question worth answering, because it decides who pays. Since 2011 a lot of the pipework people assume is theirs has not been, and plenty of households pay for work that their water company would have done.
Broadly: the drain that runs inside your property boundary and only serves your house is yours to maintain. Once the pipe leaves your boundary, or once it starts carrying waste from a neighbour's property as well, it is generally the water company's responsibility.
Across the North West that means United Utilities. If a blockage sits in the shared or public section, they will normally attend and clear it without charging you.
On 1 October 2011, most private sewers and lateral drains in England and Wales transferred into the ownership of the water and sewerage companies. Overnight, miles of pipework that had been the homeowner's problem became the water company's.
A lot of people still do not know this, which is why the question is worth asking before anyone starts quoting for excavation.
Much of the North West's older housing stock is Victorian and Edwardian terrace, and on those streets the drainage often runs shared beneath the back alley rather than straight out to the road.
That matters: a pipe taking waste from several houses is usually a shared sewer, not your private drain, even where it physically crosses your land.
You do not have to guess. A camera down the line establishes where the blockage sits relative to your boundary, which settles the question and gives you something to show the water company if it turns out to be theirs.
If it is genuinely yours, you get a clear picture of what is wrong before anyone digs anything up.
If the blockage is affecting more than one property, or there is sewage surfacing in a shared area, call United Utilities first, that is likely to be theirs and free to you. If it is only your house affected, it is more likely to be your private drain.
Then it is your side of the boundary, and a survey is the fastest way to see what is actually wrong rather than paying for guesswork.
Not sure what you are looking at? Liam will tell you straight over the phone whether it is a job that needs someone out, or something that can wait.
Call 07352 554 345